A SIM card, or subscriber identity module, is a small card in your cellphone that lets you place phone calls, send text messages, and more.

A dual-SIM setup lets you use one phone to make and receive calls and texts from two numbers. It's also super convenient and can save you serious cash when traveling. We show you how to use two SIMs ...

Pay-as-you-go cell phone provider Straight Talk employs SIM cards, allowing you to use your own unlocked GSM or CDMA phone on the network or purchase one of the phones that the company offers directly ...

Is it possible to swap SIM cards (assuming they're the same size, nano, micro, etc) between phones? The reason is simple: I'd like to see if a particular MVNO (Smart Talk, via TMobile) has any ...

As many as one quarter of all mobile phones in use in the world today could be vulnerable to an SMS attack that allows hackers to gain full control of the phone. The vulnerability was discovered in ...

A German security research lab revealed surprising security flaws in SIM cards. July 22, 2013— -- You're not going to get a text message asking to forward thousands of dollars to fund a Nigerian ...

Using two SIM cards, or enabling a dual-SIM setup, can be helpful when you need two separate phone plans on a single device. It easily lets you consolidate personal and work numbers on one phone, for ...